21106210 has 8 divisors (see below), whose sum is σ = 37991196. Its totient is φ = 8442480.

The previous prime is 21106201. The next prime is 21106213. The reversal of 21106210 is 1260112.

It can be written as a sum of positive squares in 2 ways, for example, as 17833729 + 3272481 = 4223^2 + 1809^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21106213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1055301 + ... + 1055320.

Almost surely, 2^21106210 is an apocalyptic number.

21106210 is a deficient number, since it is larger than the sum of its proper divisors (16884986).

21106210 is a wasteful number, since it uses less digits than its factorization.

21106210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2110628.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 21106210 is about 4594.1495404482. The cubic root of 21106210 is about 276.3567552836.

Adding to 21106210 its reverse (1260112), we get a palindrome (22366322).

It can be divided in two parts, 21106 and 210, that added together give a square (21316 = 146²).

The spelling of 21106210 in words is "twenty-one million, one hundred six thousand, two hundred ten".